A taste of Belfast came to Havana today when a cross-party group of Northern Ireland MPs and legislators became the first international delegation to meet leaders of the Farc, Colombia's main guerrilla organisation, since peace talks with the Colombian government began in November last year.

The negotiations in Cuba between President Juan Manuel Santos's government and the leftist Revolutionary Armed Forces of Colombia, which offer the prospect of bringing one of the world's longest and bloodiest conflicts to an end, led to a breakthrough partial agreement earlier this week on land reform, one of the core issues at the heart of the war.

The four-man delegation from Northern Ireland – including Jeffrey Donaldson from the Democratic Unionist Party and Sinn Fein's Conor Murphy, and representing all the main parties in the peace process – met President Santos and Colombian government negotiators in November and is pressing the case for a ceasefire and security guarantees for the opposition as essential to the success of the Colombian talks.

The conflict between the Farc and other guerrilla groups and the US-backed Colombian government, which began in the 1960s, has led to hundreds of thousands of deaths – mostly at the hands of the army and rightwing paramilitary forces. Large-scale human rights abuses include the assassination of thousands of trade unionists since the 1980s.

Colombia's president has been under attack by his predecessor Alvaro Uribe for agreeing to peace talks, and is anxious to close a deal before elections next year. He has refused the Farc's proposal for a ceasefire in the conflict, which has continued on the ground since the talks began. The Farc called a unilateral two-month ceasefire in November, but that has since lapsed.

After the initial agreement on land, negotiations are now expected to move on to integrating the 10,000-strong Farc into mainstream politics, tackling drug trafficking and providing justice for victims of the conflict. An earlier attempt at a peace settlement in the 1980s was derailed by the mass killing of opposition activists.

Speaking from Havana in a break from meetings with Farc leaders, the DUP's Jeffrey Donaldson said Northern Ireland showed the Colombian peace process would only work if it was inclusive. "We want to encourage a comprehensive ceasefire to create the right conditions for negotiation. We couldn't have achieved what we did without those key elements," he said.

He was echoed by Sinn Fein's Conor Murphy, who said the cross-party delegation – brought to Havana by the UK-based trade union-backed Justice for Colombia group – showed that "former enemies can make peace agreements stick", and the importance of security for guerrilla and political opposition leaders. "The fact we're in Cuba and not Colombia demonstrates that's still an issue for these negotiations," he said.

Farc negotiator Marco Leon Calarca told the Guardian the Irish experience was "very important for us because they're telling us their first hand experiences of a peace process that's been successful. There are differences in the conflicts of course, but also a lot of parallels."